class DenCli
	class UsageError < ::RuntimeError
	end
	class UnknownCommand < UsageError
	end

	require_relative 'dencli/cmd'
	require_relative 'dencli/sub'
	require_relative 'dencli/interactive'
	require_relative 'dencli/version'

	class <<self
		# Helper Function for generate Regular Expressions of string,
		# which matches all strings which has parts fron beginning of the given string.
		# `n("abc")` would produce: `/(?:a|ab|abc)/`
		# You can define a minimum length to match:
		# `n("abcdef",4)` => `/abcd(?:|e|ef)/`
		def n s, min = nil
			min ||= 1
			/#{s.length <= min ?
				Regexp.quote(s) :
				"#{Regexp.quote s[0...min]}#{
					s[min...-1].
						reverse.
						each_char.
						reduce( "#{Regexp.quote s[-1]}?") {|f,n|
							"(?:#{Regexp.quote n}#{f})?"
					}
				}"
			}/
		end

		# Wraps `n(s,min=)` in a full matching RegExp with ending `\0`:
		# `r("abc")` would produce: `/\A(?:a|ab|abc)\0\z/`
		# You can define a minimum length to match:
		# `r("abcdef",4)` => `/\aabcd(?:|e|ef)\0\z/`
		def r s, min = nil
			/\A#{n s, min}\0\z/
		end

		# Generates a list of aliases for given `cmd`:
		# `g(:abc)` => `["a", "ab", "abc"]`
		# `g(:abcdef, 4)` => `["abcd", "abcde", "abcdef"]`
		def gen_aliases cmd, min = nil
			r = ((min||1)-1).upto cmd.length-1
			if block_given?
				r.each {|i| yield cmd[0..i] }
			else
				r.map  {|i| cmd[0..i] }
			end
		end
		alias g gen_aliases
	end

	attr_reader :subs

	def initialize progname, desc
		@subs = Sub.new self, progname, desc
	end

	def full_cmd
		[]
	end

	def _full_cmd post
		post
	end

	def sub *a, &exe
		@subs.sub *a, &exe
	end

	def cmd *a, &exe
		@subs.cmd *a, &exe
	end

	def call *a
		@subs.call *a
	end

	def help *args
		@subs.help *args
	end

	def [] k
		@subs[k]
	end

	def interactive *args, **opts
		Interactive.new self, *args, **opts
	end
end